1. Field
The present disclosure relates generally to electrosurgical system, and more specifically, to a system and method for discharging excess energy of a high voltage direct current (HVDC) power supply of an electrosurgical generator.
2. Description of the Related Art
Electrosurgery involves application of high radio frequency electrical current to a surgical site to cut, seal, ablate, or coagulate tissue. In monopolar electrosurgery, a source or active electrode delivers radio frequency energy from the electrosurgical generator to the tissue and a return electrode carries the current back to the generator. In monopolar electrosurgery, the source electrode is typically part of a surgical instrument held by the surgeon and applied to the tissue to be treated. A patient return electrode is placed remotely from the active electrode to carry the current back to the generator.
In bipolar electrosurgery, a hand-held instrument typically carries two electrodes, e.g., electrosurgical forceps. One of the electrodes of the hand-held instrument functions as the active electrode and the other as the return electrode. The return electrode is placed in close proximity to the active (i.e., current supplying) electrode such that an electrical circuit is formed between the two electrodes. In this manner, the applied electrical current is limited to the body tissue positioned between the two electrodes.
Conventional electrosurgical generators include a high voltage direct current (HVDC) power connected to a radio frequency (RF) output stage, which converts DC energy generated by the HVDC into RF energy. The high voltage direct current (HVDC) power supply includes an output filter which smoothes the switching of the HVDC into a DC level. This filter can store large amount of energy and under light loads and high impedance, the discharge of the output filter is slow. As a result, the generator response time is significantly lowered thereby limiting the generator's ability to pulse energy rapidly or respond quickly during light loads.
Therefore, there is a need for an electrosurgical generator which can discharge energy in a consistent and rapid manner under various load conditions, including light loads and high impedance.